1. Field of the Invention
The present invention relates to a motor actuator incorporated, for example, in automobile air-conditioner for actuating an air-mix door of the air-conditioner.
2. Description of the Prior Art
A typical example of motor actuators of the type concerned is disclosed, for example, in Japanese Patent Laid-open Publication No. 58-209609. The disclosed motor actuator is used for actuating an air-mix door and includes a mechanical switch for producing control signals used for mode selection and fan controlling. The changeover signal issued from the mechanical switch is employed in an external control circuit.
When controlled with the known motor actuator, the air-mix door is actuated to turn or angularly move between a full-cool position and a full-heat position.
Such a mere setting of the air-mix door in two extreme positions does not guarantee a comfortable air-conditioning feeling when the air-conditioner is operating in a certain discharge mode.
For instance, when the air-mix door is set in the full-heat position while air-conditioner is operating in the vent mode, high temperature air is directed to the face of an occupant, thus deteriorating the air-conditioning feeling.
Another drawback associated with the prior art motor actuator is that the switch mechanism disposed in the motor actuator for producing control signals for various components of the air-conditioner is mutually wasteful when mode selection of the actuator motor is controlled by a computer. With this wasteful switch mechanism, the cost of the prior art motor actuator is considerably high.